Depth camera assembly, device for collecting depth image and multi-sensor fusion system

ABSTRACT

A depth camera assembly is provided. The depth camera assembly includes: a depth camera, configured to generate a trigger signal, in which the trigger signal is configured to instruct the depth camera to perform a first exposure operation to obtain first image information; a red-green-blue (RGB) camera, communicatively connected to the depth camera to receive the trigger signal, in which the trigger signal is configured to instruct the RGB camera to perform a second exposure operation to obtain second image information; and a processor, communicatively connected respectively to the depth camera and the RGB camera to receive the trigger signal, the first image information and the second image information, and configured to record a time stamp of the first image information and the second image information based on local time of receiving the trigger signal.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims priority to Chinese PatentApplication No. 202210302614.X, filed on Mar. 24, 2022, the entirecontent of which is incorporated herein by reference for all purposes.

TECHNICAL FIELD

The disclosure relates to the field of terminal technologies, and moreparticularly, to a depth camera assembly, a device for collecting adepth image and a multi-sensor fusion system.

BACKGROUND

For some RGB-D (Red-Green-Blue-Depth) cameras currently on the market,they can obtain image information and depth information respectively.

SUMMARY

According to a first aspect of the disclosure, a depth camera assemblyis provided, including: a depth camera, configured to generate a triggersignal, in which the trigger signal is configured to instruct the depthcamera to perform a first exposure operation to obtain first imageinformation; a red-green-blue (RGB) camera, communicatively connected tothe depth camera to receive the trigger signal, in which the triggersignal is configured to instruct the RGB camera to perform a secondexposure operation to obtain second image information; and a processor,communicatively connected to the depth camera and the RGB camerarespectively to receive the trigger signal, the first image informationand the second image information, and configured to record a time stampof the first image information and the second image information based onlocal time of receiving the trigger signal.

According to a second aspect of the disclosure, a device for collectinga depth image is provided, including: the depth camera assembly asdescribed according to the first aspect, and a global position system(GPS) module, communicatively connected to the depth camera assembly,and configured to update local time of the processor of the depth cameraassembly.

According to a third aspect of the disclosure, a multi-sensor fusionsystem is provided, including: a master sensor including the depthcamera assembly according to the first aspect; and one or more slavesensors, in which each slave sensor includes a second trigger signalinput end for receiving the trigger signal output by the depth cameraassembly, and configured to perform a third exposure operation based onthe trigger signal.

According to a fourth aspect of the disclosure, an autonomous mobiledevice is provided, including: the multi-sensor fusion system accordingto the third aspect.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments consistent with thedisclosure and, together with the description, serve to explain theprinciples of the disclosure.

FIG. 1 is a block diagram of a depth camera assembly according toembodiments.

FIG. 2 is a block diagram of a device for collecting a depth imageaccording to embodiments.

FIG. 3 is a block diagram of a multi-sensor fusion system according toembodiments.

FIG. 4 is a block diagram of another multi-sensor fusion systemaccording to embodiments.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments, examples of whichare illustrated in the accompanying drawings. The following descriptionrefers to the accompanying drawings in which the same numbers indifferent drawings represent the same or similar elements unlessotherwise represented. The implementations set forth in the followingdescription of embodiments do not represent all implementationsconsistent with the disclosure. Instead, they are merely examples ofapparatuses and methods consistent with aspects related to thedisclosure as recited in the appended claims.

Terms used in the disclosure are merely for describing specific examplesand are not intended to limit the disclosure. The singular forms “one”,“the”, and “this” used in the disclosure and the appended claims arealso intended to include a multiple form, unless other meanings areclearly represented in the context. It should also be understood thatthe term “and/or” used in the disclosure refers to any or all possiblecombinations including one or more associated listed items.

Although terms “first”, “second”, “third”, and the like are used in thedisclosure to describe various information, the information is notlimited to the terms. These terms are merely used to differentiateinformation of a same type. For example, without departing from thescope of the disclosure, first information is also referred to as secondinformation, and similarly the second information is also referred to asthe first information. Depending on the context, for example, the term“if” used herein can be explained as “when” or “while”, or “in responseto . . . , it is determined that”.

For an imaging quality of RGB-D cameras, it needs to record imageinformation and depth information at the same time, to process to obtainhigh-quality data information. If image information is not combined withdepth information at the same time, it can result in image distortionand poor user experience. The disclosure provides a depth cameraassembly, a device for collecting a depth image and a multi-sensorfusion system, to solve deficiencies in the related art.

FIG. 1 is a block diagram of a depth camera assembly 100 according toembodiments and FIG. 2 is a block diagram of a device for collecting adepth image according to embodiments. As illustrated in FIG. 1 and FIG.2 , the depth camera assembly 100 includes a depth camera 1, an RGBcamera 2 and a processor 3. The processor 3 is communicatively connectedto the depth camera 1 and the RGB camera 2 respectively to obtain firstimage information detected by the depth camera 1 and second imageinformation detected by the RGB camera 2. The depth camera 1 and theprocessor 3 can be connected by a data wire connection or a wirelessconnection, and similarly, the RGB camera 2 and the processor 3 can beconnected by a data wire connection or a wireless connection, which isnot limited in the disclosure.

In detail, the depth camera 1 is configured to generate a triggersignal. The trigger signal is configured to instruct the depth camera 1to perform a first exposure operation, thereby obtaining first imageinformation. The depth camera 1 can also be communicatively connected tothe RGB camera 2 and the RGB camera 2 can receive the trigger signalsent by the depth camera 1. The trigger signal can also be configured toinstruct the RGB camera 2 to perform a second exposure operation,thereby obtaining second image information. The processor 3 can receivethe trigger signal and the first image information through thecommunication connection with the depth camera 1, receive the secondimage information through the communication connection with the RGBcamera 2, and record the local time of receiving the trigger signal asthe time when the depth camera 1 and the RGB camera 2 are triggered, sothat the time stamp of the first image information and the second imageinformation can be recorded based on the local time.

Based on the technical solutions of the disclosure, when the depthcamera 1 is triggered by the trigger signal, the RGB camera 2 can alsobe triggered based on the received trigger signal, so that the depthcamera 1 and the RGB camera 2 can be triggered at the same time, whichis beneficial to obtain the first image information and the second imageinformation at the same time to improve the fusion accuracy between thefirst image information and the second image information. The processor3 can record the timestamp of the first image information and the secondimage information based on the same local time, which is also beneficialto the fusion accuracy between the first image information and thesecond image information at the same time. The trigger signal caninclude a high-frequency pulse signal, such as a high-frequency pulsesignal of 20 Hz or 30 Hz.

In some embodiments, the depth camera 1 can include a trigger signalgenerating module 11, a trigger signal output end 12 and a first imageinformation output end 13. The trigger signal generating module 11 isconnected to the trigger signal output end 12 to output the triggersignal generated by the trigger signal generating module 11 through thetrigger signal output end 12. The RGB camera 2 includes a first triggersignal input end 21 and a second image information output end 22. Thefirst trigger signal input end 21 can be communicatively connected tothe trigger signal output end 12, so that the trigger signal generatedby the trigger signal generating module 11 can be obtained through thefirst trigger signal input end 21. The processor 3 can include a firstinput end 31 and a second input end 32. The first input end 31 can becommunicatively connected to the trigger signal output end 12 to receivethe trigger signal output by the trigger signal output end 12 throughthe first input end 31. The second input end 32 can be connected to thefirst image information output end 13 and the second image informationoutput end 22 respectively, to receive the first image information andthe second image information through the second input end 32. As shownin FIG. 2 , the processor 3 can include a plurality of second input ends32, in which one second input end 32 is configured to receive the firstimage information and another second input end 32 is configured toreceive the second image information. In other embodiments, theprocessor 3 can also include a single second input end 32, and the firstimage information and the second image information are received throughthe single second input end 32, which is not limited in the disclosure.The high-frequency pulse signal is connected to the first input end 31of the processor 3. When a trigger edge (a rising edge or a fallingedge) of the high-frequency pulse signal is received, a second interruptsignal is generated, the local time corresponding to the secondinterrupt signal is read, and the local time corresponding to the secondinterrupt signal is recorded as the timestamp of the first imageinformation and the second image information based on the local time.

Further, in order to improve the fusion accuracy between the depthcamera assembly 100 and other sensor data, as shown in FIG. 2 , theprocessor 3 can further include a third input end 33 and a serial portinput end 34. The device for collecting a depth image can also include aGPS module 200. The GPS module can be communicatively connected to thedepth camera assembly 100 to update the local time of the processor 3through the GPS module. In detail, the GPS module 200 can include a PPS(Pulse Per Second) signal output end 201 and a serial port output end202. The PPS signal output end 201 can be connected to the third inputend 33 of the processor 3, and the serial port output end 202 can beconnected to the serial port input end 34 of the processor 3. Theprocessor 3 can receive the PPS pulse signal sent by the PPS signaloutput end 201 through the third input end 33, and receive the serialport signal output by the serial port output end 202 through the serialport input end 34.

The processor 3 can record first local time when a target edge of thePPS pulse signal is received, analyze universal time coordinated (UTC)time when the target edge of the PPS pulse signal is received based onthe received serial port signal, record second local time when the UTCtime is obtained at the same time, determine current UTC timecorresponding to the second local time based on the first local time,the second local time and the UTC time, and update local time of theprocessor 3 based on the current UTC time. In detail, the current UTCtime is defined as the new second local time, so that the local time ofthe processor 3 can be aligned with the UTC time. It can be understoodthat the GPS module 200 can obtain the standard time signal from GPSsatellites. Furthermore, the local time of the processor can be updatedthrough the interaction between the GPS module 200 and the processor 3based on the standard time signal, to reduce or eliminate the deviationbetween the local time and the standard time signal, which is beneficialto realize the time alignment between the depth camera assembly 100 andother sensors through the standard time signal and is convenient for thefusion between the data of the depth camera assembly 100 and othersensors. Compared with the scheme of timing by the local clock of theprocessor 3, the offset between the local time of processor 3 and theUTC time is reduced or eliminated. The processor 3 can generate thefirst interrupt signal when the target edge of the PPS pulse signal isreceived through the third input end 33, and the processor 3 can obtainthe accurate local time when the target edge occurs by recording thetime of the first interrupt signal, that is, obtain the first localtime, which can effectively ensure the reliability of the first localtime.

The serial port signal can include GPRMC data or GPGGA data output bythe GPS module 200. The GPS module 200 can output a piece of GPRMC dataor GPGGA data after each output of the PPS pulse signal, and theprocessor 3 can obtain the UTC time of the target edge by parsing theGPRMC data or GPGGA data. The target edge can include a rising edge or afalling edge of the PPS pulse signal. When the target edge is the risingedge, the processor 3 can obtain the UTC time corresponding to therising edge by parsing the GPRMC data or GPGGA data. When the targetedge is the falling edge, the processor 3 can obtain the UTC timecorresponding to the falling edge by parsing the GPRMC data or GPGGAdata. The GPGGA data is a GPS data output format statement, whichusually includes 17 fields: statement header, world time, latitude,latitude hemisphere, longitude, longitude hemisphere, positioningquality indication, number of satellites used, horizontal precisionfactor, ellipsoid height, altitude unit, geoid height anomalydifference, height unit, differential GPS data period, differentialreference base station label, checksum tag and end tag, separated bycommas.

In the above embodiments, the processor 3 can further include acalculating module. It is assumed that the first local time is T1, theUTC time is T2, the second local time is T3, and the current UTC timecorresponding to the second local time, which needs to be determined bythe processor 3, is T4. In some embodiments, the difference between thefirst local time T1 and the second local time T3, recorded based on thelocal time of the processor 3 before the update, can be defined as thedifference between the UTC time T2 and the current UTC time T4corresponding to the second local time T3. Therefore, the calculatingmodule can calculate the current UTC time T4 based on the sum of thedifference between the second local time T3 and the first local time T1and the UTC time T2, that is, T4=T2+(T3-T1). In other embodiments, sincethere can be a certain error between the local time of the processor 3before the update and the UTC time, the difference between the firstlocal time T1 and the second local time T3 can be calibrated, and thencan be summed with the UTC time T3 to calculate the current UTC time T4.The calibration manner can be that the difference between the firstlocal time T1 and the second local time T3 is multiplied by the weightor can be that the difference between the first local time T1 and thesecond local time T3 minus or plus a calibration value, in which thecalibration value can be obtained based on experiments, which is notlimited in the disclosure.

Further, the GPS module 200 continuously sends the PPS pulse signal tothe processor 3 at a certain frequency. In fact, in some cases, when theerror of the local time of the processor 3 is within an allowable range,the local time may not be updated, thereby reducing the resource wasteof the processor 3. Therefore, the processor 3 can also consider thatthe error of the local time currently used by the processor 3 exceedsthe allowable range when the difference between the second local time T3and the current UTC time T4 is greater than a preset threshold.Therefore, the local time is updated based on the UTC time T4.

Based on the technical solutions of the disclosure, as shown in FIG. 3 ,the disclosure further provides a multi-sensor fusion system. Themulti-sensor fusion system includes a master sensor and a slave sensor301. The master sensor can include the depth camera assembly 100 in anyone of the above-mentioned embodiments. The slave sensor 301 can includea second trigger signal input end 3011. The second trigger signal inputend 3011 can be connected to the trigger signal output end 12 of thedepth camera assembly 100, so that the trigger signal output by thedepth camera 1 can be received by the second trigger signal input end3011, and the slave sensor 301 can perform the third exposure operationbased on the received trigger signal.

Each slave sensor 301 can include one or more cameras, and at least onecamera can be provided with the second trigger signal input end 3011.The trigger signal output end 12 of the depth camera 1 can be connectedto the second trigger signal input end of the at least one camera, totrigger the corresponding camera to perform the third exposureoperation. For example, each slave sensor 301 can include a depth camera1 and an RGB camera or can also include other telephoto camera orwide-angle camera, which is not limited in the disclosure. In someembodiments of the disclosure, the fusion system includes a single slavesensor 301 as an example for illustration. In other embodiments, thefusion system can also include multiple slave sensors 300, and at leastone of the multiple slave sensors 300 can be triggered by the depthcamera 1 of the master sensor.

Based on this, in the fusion system, other cameras included in themaster sensor can be triggered simultaneously through the depth camera 1of the master sensor, and the slave sensor 301 can also be triggeredthrough the depth camera 1 of the master sensor at the same time, torealize the synchronous triggering between the master sensor and theslave sensor 301, which is beneficial to obtain the target image at thesame time, reduce the fusion error between subsequent image information,and improve the fusion accuracy.

As shown in FIG. 4 , the fusion system can also include a GPS module 200and a host 302. The GPS module 200 can be configured to update the localtime of the master sensor and the slave sensor 301, so that the mastersensor and the slave sensor can record the time stamp of obtained imageinformation based on the updated local time. The host 302 can becommunicatively connected to the master sensor and the slave sensor 301respectively. For example, in some embodiments provided by thedisclosure, the communication connection can be made through a USB dataline. In other embodiments provided by the disclosure, the communicationconnection between the host 302 and the master sensor and the slavesensor 301 can also be realized by means of wireless communication. Thehost 302 is configured to receive the image information obtained by themaster sensor and the slave sensor, and process and fuse the imageinformation based on the time stamp. Based on this, the time is updatedby the GPS module 200, which can align the local time of the mastersensor and the slave sensor with the world time, and reduce the fusionerror caused by the time error of the master sensor and the slave sensoritself. The specific implementation of the GPS module 200 updating thelocal time of the master sensor and the slave sensor can refer to theforegoing embodiments, which will not be repeated herein.

Still as shown in FIG. 4 , the GPS module 200 can also becommunicatively connected to the host 302. The positioning function ofthe GPS module 200 may be used to locate absolute positioninginformation of the autonomous mobile device located by the GPS module200. The absolute positioning information is relative to the earthcoordinate system. The host is configured to obtain the absolutepositioning information and obtain relative positioning information ofthe autonomous mobile device based on the image information. Therelative positioning information can be based on any reference point inthe traveling process of the autonomous mobile device. In detail, theSlam fusion algorithm can be used to obtain the relative positioninginformation.

The absolute positioning information and the relative positioninginformation can be both configured to plan a movement path of theautonomous mobile device. For example, in some places or areas with weakGPS signals, the relative positioning information can be configured toplan the movement path. In some places or areas with good GPS signals,the movement path can be planned through the absolute positioninginformation, thereby improving the movement accuracy. At the same time,the absolute positioning information can also be used to correct theerror of the relative positioning information. For example, the absolutepositioning information of the reference point and the absolutepositioning information of the current position point can be compared toobtain the distance between the reference point and the current positionpoint to correct the relative positioning information. The positioninginformation obtained by the GPS module 200 can be output through theserial port output end 202, and then sent to the host 302 through theserial port to USB module of the fusion system.

It should be noted that the embodiments shown in FIG. 3 and FIG. 4 areonly used for exemplary illustration. In other embodiments, themulti-sensor fusion system can also include other sensors, such as amicrophone module or an IMU (inertial measurement unit) sensor. There isno limit to the disclosure. As shown in FIG. 3 , the multi-sensor fusionsystem can include a single slave sensor, or as shown in FIG. 4 , themulti-sensor fusion system can include two slave sensors, or in otherembodiments, the multi-sensor fusion system can also include three ormore slave sensors, which is not limited in the disclosure.

Based on the technical solutions of the disclosure, an autonomous mobiledevice is also provided. The autonomous mobile device can include themulti-sensor fusion system described in any of the above embodiments,and the autonomous mobile device can include an autonomous vehicle, anunmanned aerial vehicle, or the like, which is not limited in thedisclosure.

The solutions provided by embodiments of the disclosure can include thefollowing beneficial effects. It can be known from the above embodimentsthat when the depth camera generates the trigger signal to trigger thedepth camera, the trigger information can also be transmitted to triggerthe RGB camera through the trigger signal, to realize the simultaneoustriggering of the depth camera and the RGB camera, which is beneficialto obtain the first image information and the second image informationat the same time to improve the fusion accuracy between the first imageinformation and the second image information. The processor can recordthe timestamp of the first image information and the second imageinformation based on the same local time, which is also beneficial tothe fusion accuracy between the first image information and the secondimage information at the same time.

Other embodiments of the disclosure will be apparent to those skilled inthe art from consideration of the specification and practice of thedisclosure disclosed here. This application is intended to cover anyvariations, uses, or adaptations of the disclosure following the generalprinciples thereof and including such departures from the disclosure ascome within known or customary practice in the art. It is intended thatthe specification and examples be considered as exemplary only, with atrue scope and spirit of the disclosure being indicated by the followingclaims.

It will be appreciated that the disclosure is not limited to the exactconstruction that has been described above and illustrated in theaccompanying drawings, and that various modifications and changes can bemade without departing from the scope thereof. It is intended that thescope of the disclosure only be limited by the appended claims.

What is claimed is:
 1. A depth camera assembly, comprising: a depthcamera, configured to generate a trigger signal, wherein the triggersignal is configured to instruct the depth camera to perform a firstexposure operation to obtain first image information; a red-green-blue(RGB) camera, communicatively connected to the depth camera to receivethe trigger signal, wherein the trigger signal is configured to instructthe RGB camera to perform a second exposure operation to obtain secondimage information; and a processor, communicatively connectedrespectively to the depth camera and the RGB camera to receive thetrigger signal, the first image information and the second imageinformation, and configured to record a time stamp of the first imageinformation and the second image information based on local time ofreceiving the trigger signal.
 2. The depth camera assembly as claimed inclaim 1, wherein: the depth camera comprises a trigger signal generatingmodule, a trigger signal output end and a first image information outputend, the trigger signal generating module is connected to the triggersignal output end, and the trigger signal generating module isconfigured to generate the trigger signal; the RGB camera comprises afirst trigger signal input end and a second image information outputend, the first trigger signal input end is communicatively connected tothe trigger signal output end to obtain the trigger signal through thetrigger signal output end; and the processor comprises a first input endand a second input end, the first input end is communicatively connectedto the trigger signal output end to obtain the trigger signal throughthe trigger signal output end, and the second input end is respectivelyconnected to the first image information output end and the second imageinformation output end to obtain the first image information and thesecond image information.
 3. The depth camera assembly as claimed inclaim 1, wherein the processor further comprises: a third input end,connected to a pulse per second (PPS) signal output end of a globalposition system (GPS) module to receive a PPS pulse signal output by thePPS signal output end; and a serial port input end, connected to aserial port output end of the GPS module to receive a serial port signaloutput by the serial port output end; wherein the processor isconfigured to record first local time in response to receiving a targetedge of the PPS pulse signal, analyze universal time coordinated (UTC)time in response to receiving the target edge based on the serial portsignal, and record second local time in response to obtaining the UTCtime, to determine current UTC time corresponding to the second localtime based on the first local time, the second local time and the UTCtime, and update local time of the processor based on the current UTCtime.
 4. The depth camera assembly as claimed in claim 3, wherein theprocessor further comprises: a calculating module, configured tocalculate the current UTC time based on a sum of: a difference betweenthe second local time and the first local time, and the UTC time.
 5. Thedepth camera assembly as claimed in claim 4, wherein the processor isconfigured to update the local time in response to a difference betweenthe second local time and the current UTC time being greater than apreset threshold.
 6. A device for collecting a depth image, comprising:a depth camera, configured to generate a trigger signal, wherein thetrigger signal is configured to instruct the depth camera to perform afirst exposure operation to obtain first image information; ared-green-blue (RGB) camera, communicatively connected to the depthcamera to receive the trigger signal, wherein the trigger signal isconfigured to instruct the RGB camera to perform a second exposureoperation to obtain second image information; a processor,communicatively connected respectively to the depth camera and the RGBcamera to receive the trigger signal, the first image information andthe second image information, and configured to record a time stamp ofthe first image information and the second image information based onlocal time of receiving the trigger signal; and a global position system(GPS) module, configured to update local time of the processor.
 7. Thedevice as claimed in claim 6, wherein: the depth camera comprises atrigger signal generating module, a trigger signal output end and afirst image information output end, the trigger signal generating moduleis connected to the trigger signal output end, and the trigger signalgenerating module is configured to generate the trigger signal; the RGBcamera comprises a first trigger signal input end and a second imageinformation output end, the first trigger signal input end iscommunicatively connected to the trigger signal output end to obtain thetrigger signal through the trigger signal output end; and the processorcomprises a first input end and a second input end, the first input endis communicatively connected to the trigger signal output end to obtainthe trigger signal through the trigger signal output end, and the secondinput end is respectively connected to the first image informationoutput end and the second image information output end to obtain thefirst image information and the second image information.
 8. The deviceas claimed in claim 6, wherein the processor further comprises a thirdinput end and a serial port input end; and the GPS module comprises apulse per second (PPS) signal output end and a serial port output end;the third input end is connected to the PPS signal output end to receivea PPS pulse signal output by the PPS signal output end; the serial portinput end is connected to the serial port output end to receive a serialport signal output by the serial port output end; and the processor isconfigured to record first local time in response to receiving a targetedge of the PPS pulse signal is received, analyze universal timecoordinated (UTC) time in response to receiving the target edge based onthe serial port signal, and record second local time in response toobtaining the UTC time, to determine current UTC time corresponding tothe second local time based on the first local time, the second localtime and the UTC time, and update local time of the processor based onthe current UTC time.
 9. The device as claimed in claim 8, wherein theprocessor further comprises: a calculating module, configured tocalculate the current UTC time based on a sum of: a difference betweenthe second local time and the first local time, and the UTC time. 10.The device as claimed in claim 9, wherein the processor is configured toupdate the local time in response to a difference between the secondlocal time and the current UTC time being greater than a presetthreshold.
 11. A multi-sensor fusion system, comprising: a master sensorcomprising: a depth camera, configured to generate a trigger signal,wherein the trigger signal is configured to instruct the depth camera toperform a first exposure operation to obtain first image information; ared-green-blue (RGB) camera, communicatively connected to the depthcamera to receive the trigger signal, wherein the trigger signal isconfigured to instruct the RGB camera to perform a second exposureoperation to obtain second image information; and a processor,communicatively connected respectively to the depth camera and the RGBcamera to receive the trigger signal, the first image information andthe second image information, and configured to record a time stamp ofthe first image information and the second image information based onlocal time of receiving the trigger signal; and one or more slavesensors, wherein each slave sensor comprises a second trigger signalinput end for receiving the trigger signal output by the depth camera,and configured to perform a third exposure operation based on thetrigger signal.
 12. The system as claimed in claim 11, furthercomprising: a global position system (GPS) module, configured to updatelocal time of the master sensor and the one or more slave sensors, andthe master sensor and the one or more slave sensors are configured torecord a timestamp of obtained image information based on the updatedlocal time; and a host, communicatively connected to the master sensorand the one or more slave sensors respectively, and configured toreceive image information obtained by the master sensor and the one ormore slave sensors, and process and fuse the image information based onthe timestamp.
 13. The system as claimed in claim 12, wherein: the GPSmodule is communicatively connected to the host, and further configuredto locate absolute positioning information of an autonomous mobiledevice to which the system belongs; and the host is further configuredto obtain the absolute positioning information and obtain relativepositioning information of the autonomous mobile device based on theimage information, and both the absolute positioning information and therelative positioning information is configured to plan a movement pathof the autonomous mobile device.
 14. The system as claimed in claim 11,wherein: the depth camera comprises a trigger signal generating module,a trigger signal output end and a first image information output end,the trigger signal generating module is connected to the trigger signaloutput end, and the trigger signal generating module is configured togenerate the trigger signal; the RGB camera comprises a first triggersignal input end and a second image information output end, the firsttrigger signal input end is communicatively connected to the triggersignal output end to obtain the trigger signal through the triggersignal output end; and the processor comprises a first input end and asecond input end, the first input end is communicatively connected tothe trigger signal output end to obtain the trigger signal through thetrigger signal output end, and the second input end is respectivelyconnected to the first image information output end and the second imageinformation output end to obtain the first image information and thesecond image information.
 15. The system as claimed in claim 11, whereinthe processor further comprises a third input end and a serial portinput end; and the GPS module comprises a pulse per second (PPS) signaloutput end and a serial port output end; the third input end isconnected to the PPS signal output end to receive a PPS pulse signaloutput by the PPS signal output end; the serial port input end isconnected to the serial port output end to receive a serial port signaloutput by the serial port output end; and the processor is configured torecord first local time in response to receiving a target edge of thePPS pulse signal, analyze universal time coordinated (UTC) time inresponse to receiving the target edge based on the serial port signal,and record second local time in response to obtaining the UTC time, todetermine current UTC time corresponding to the second local time basedon the first local time, the second local time and the UTC time, andupdate local time of the processor based on the current UTC time. 16.The system as claimed in claim 15, wherein the processor furthercomprises: a calculating module, configured to calculate the current UTCtime based on a sum of: a difference between the second local time andthe first local time, and the UTC time.
 17. The system as claimed inclaim 16, wherein the processor is configured to update the local timein response to a difference between the second local time and thecurrent UTC time being greater than a preset threshold.
 18. Anautonomous mobile device, comprising: the multi-sensor fusion system asclaimed in claim 11.